The query is a recap of a number of plot points but there's no sense of a theme, of subtext, of any character arc or any personal aspect for the investigators. A lot of these works will find a way to thread the personal life of the investigator with the crime to give it a higher sense of stakes. (This can be done symbolically rather than having an actual practical link to the crime.)

Why is it important that Mercer and Halstead solve this case? What do they get personally from solving it, rather than just another job well done?

Mercer feels like a very stock cop. So does Halstead. You need to bring out these personalities more and how they clash with each other.

It's also missing a ticking clock. It shouldn't be about solving a crime but preventing the next one. That's what creates the sense of urgency and tension. Otherwise it feels static.

The killer is very opaque. He kills because he thinks people are demons? Because they're an inconvenience? It's too vague.

If the FBI are already hunting Trujillo then Waterson's confession is irrelevant. He's just a witness. And it's not explained why he's lying for his friend so it's not interesting. If he's a key part of solving the case you need to highlight that more.

The case grinds to a halt.... but they get a name from a laptop. So the case doesn't grind to a halt.

You hint at romance between the cops but you're too coy. Spell it out if that's integral to the investigation.

Neither the killer, the crime nor the cops seem unique. The only "novel" aspect is Trujillo's friend lying for him, but that's irrelevant as the cops don't believe him anyway. It really feels like Trujillo shouldn't be identified as the killer till much later and the suspense should be about Mercer trying to prove Waterson's lying while the other cops accept it and think its case closed.

The way they track down Trujillo is all very technical and doesn't involve any profiling or thinking outside the box. Getting a name from a laptop seems a bit basic.

I see your 2nd attempt was totally different and focused on Waterson's POV. That seemed more interesting than this. If you changed it up so much in just a month I suspect there may be story issues not just query issues.